PNS Flashcards
What do somatic afferent nerves do?
convey information from skin, skeletal muscle and joints
What do somatic efferent nerves do?
convey information to skeletal muscles
What is a dermatome?
an area of skinthat is supplied by a single spina lnerve
What is a myotome?
group of muscles innervated by a single spinal nerve
What do visceral afferent nerves do?
carry information from the viscera (thoracic, abdominal & pelvic organs)
What do visceral efferent nerves do?
innervate the viscera (organs) + periphery (vasculature + sweat glands)
How can visceral efferent nerves be classified?
→ sympathetic
→ parasympathetic
What is the difference in areas being innervated by visceral sympathetic and parasympathetic?
Parasympathetic only innervates the viscera (organs)
What is the difference between a ganglion and a nucleus?
→ Ganglion: collection of cell bodies OUTSIDE the CNS
→ Nucleus: collection of cell bodies INSIDE the CNS
Where are the cell bodies of all PNS afferent nerve fibres?
Spinal ganglia
Where do visceral efferent nerves synapse?
Peripheral ganglion
What is a plexus?
network of interconnecting nerves
How are peripheral nerves arranged?
In fasciculi - 3 layers of connective tissue
What are the 3 layers of connective tissue in fasciculi?
→ epineurium = External vascular layer of fasciculi
→ perineurium = Covers individual fascicles
→ endoneurium = covers individual axons
What 2 classification systems are used to classify peripheral nerves?
→ conductional velocity
→ axonal diameter
How does the conduction velocity system work?
Uses ABC, A = fastest
How does the axonal diameter system work?
Uses Roman numerals I-IV, I = largest diameter
What 2 classification systems are used to classify sensory receptors?
→ source of stimulus
→ mode of detection
How are sensory receptors classified by source of stimulus?
→ detection of internal info e.g. Exteroreceptors
→ detection of internal info eg. proprioceptors, enteroreceptors
What do exteroreceptors detect?
Pain + temperature + touch + pressure
What do proprioceptors detect?
Receptors in muscles + joints, detects movement + joint position
What do enteroreceptors detect?
→ Movement through gut
→ blood ph
Give 3 examples of proprioceptors.
→ joint receptors - found in joint capsules and
detect the start and the end of movement
→ muscle spindles - detect changes in muscle length
→ Golgi tendon organs - detect changes in tension in tendons
Name 5 different types of sensory receptors.
- Chemoreceptors: detect molecules which bind to receptor
- Photoreceptors: detect light in retina
- Thermoreceptors: detect temperature in skin
- Mechanoreceptors: detect mechanical pressure or distortion
- Nociceptors: detect tissue damage, interpreted as pain
